first steps to convert TigerTreeVisualizer to Salt: compiles but is not working yet
also use sdocumentgraph for rtl detection
Merge branch 'tigerseg' into feature/treeorphans

Conflicts:
	annis-visualizers/src/main/java/annis/visualizers/component/tree/AnnisGraphTools.java
	annis-visualizers/src/main/java/annis/visualizers/component/tree/ConstituentLayouter.java
	annis-visualizers/src/main/java/annis/visualizers/component/tree/HorizontalOrientation.java
	annis-visualizers/src/main/java/annis/visualizers/component/tree/TigerTreeVisualizer.java
	annis-visualizers/src/main/java/annis/visualizers/component/tree/TreeElementStyler.java
more safe way of getting the relannis features
correct the detection of roots
restore the old behavior to not include orphan tokens